J/A+A/692/A191 Solar wind times of Fe and O signals (Gu+, 2024)
Short-term anti-correlations between in situ averaged charge states of Fe and O
in the solar wind.
Gu C., Heidrich-Meisner V., Wimmer-Schweingruber R.F.
<Astron. Astrophys. 692, A191 (2024)>
=2024A&A...692A.191G 2024A&A...692A.191G (SIMBAD/NED BibCode)
ADC_Keywords: Sun
Keywords: Sun: corona - Sun: coronal mass ejections (CMEs) - solar wind
Abstract:
Observations of the Fe and O charge states in the solar wind and
interplanetary coronal mass ejections (ICMEs) generally exhibit a
positive correlation between the average charge states of Fe and O
(avQFe and avQO). Because Fe and O charge states freeze at different
heights in the corona, this positive correlation indicates that
conditions at different heights in the corona vary as a whole.
We identify short time periods in the solar wind that exhibit
anticorrelations between the average Fe and O charge states and
investigate their properties. We aim to distinguish whether these
anticorrelations are due to the related solar sources or to transport
effects (e.g., differential streaming). We study kinetic properties of
the solar wind related to these anticorrelated structures as well as
heavy ion differential streaming in order to infer a possible
relationship between conditions in coronal source regions and the
reported in situ measurements.
We employed a recently developed sliding-window cross-correlation
method to locate anticorrelated structures in the solar wind
composition measurements between 2001 and 2010 from the Advanced
Composition Explorer (ACE). To account for fluctuations and
measurement uncertainties, we varied the timescales and temporal lags.
We determined the onset and end times of the gradual increases or
decreases in the average charge states of O and Fe and analyzed the
kinetic and plasma properties of the anticorrelated structures.
We identified 103 anticorrelated structures both in the solar wind and
in ICMEs. The behavior of avQFe is strongly related to solar wind
kinetic properties, including proton speed, proton temperature, and
the proton-proton collisional age. We find that the anticorrelation of
avQFe and avQO during these time periods cannot be explained by
differential streaming nor by unrecorded hot plasma ejections. Thus,
the measured anticorrelated variations in avQFe and avQO probably
indicate that changes in coronal conditions at different freeze-in
heights may follow opposite monotonic trends.
Description:
This table lists the 103 anti-correlated structures identified in
the paper.
The start and end times of Fe signal and O signal in each
anti-correlated structure are given.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
appendix.dat 112 103 List of the 103 anti-correlated structures
identified in paper
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Byte-by-byte Description of file: appendix.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [1/103] Event sequence number
5- 8 I4 yr Year Year
10- 21 F12.8 d ST1 The start time of Fe signal, in day of year,
based on the weak solution
23- 34 F12.8 d ET1 The end time of Fe signal, in day of year,
based on the weak solution
36- 47 F12.8 d ST2 The start time of O signal, in day of year,
based on the weak solution
49- 60 F12.8 d ET2 The end time of O signal, in day of year,
based on the weak solution
62- 73 F12.8 d ST3 The start time of Fe signal, in day of year,
based on the strong solution
75- 86 F12.8 d ET3 The end time time of Fe signal, in day of year,
based on the strong solution
88- 99 F12.8 d ST4 The start time of O signal, in day of year,
based on the strong solution
101-112 F12.8 d ET4 The end time time of O signal, in day of year,
based on the strong solution
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Acknowledgements:
Chaoran Gu, chaorangu(at)physik.uni-kiel.de
(End) Patricia Vannier [CDS] 22-Oct-2024